                Patent document 1: JP-2003-224990 A        Patent document 1: JP-2006-114869 A        Patent document 1: JP-2006-347495 A        
While an in-vehicle navigation apparatus is developed for achieving high performances, a CPU provided in a circuit board of the navigation apparatus continues significant enhancement in a processing performance. In connection, the power consumption of the CPU increases and a heat dissipation of the CPU also increases. Accordingly, also in the circuit board in the navigation apparatus, a cooling capability against the heat dissipation of the CPU has been needed in recent years.
Specifically, a fan cooling structure dedicated for the CPU becomes common as a method for improving the cooling capability. In order to anticipate such tendency further proceeding, the number of fans or rotational frequencies of fans may be increased further, or sizes of fans may be enlarged further for enhancing the cooling capability. Thus, the operating sound of the fans may increase to be thereby expected to increase aggravation of the marketability of the navigation apparatus.
Patent documents 1 to 3 describe technologies to solve such a problem. Such technologies provide a method to estimate a loudness level of sounds in a vehicle compartment by detecting an amount of audio sounds, an amount of air-conditioner air blasting, a travel speed, an engine speed value, window opening and closing, etc. The rotational frequency of the cooling fan is thereby increased such that the operating sound does not provide the problem to thereby securing or maintaining the cooling capability.
In contrast, a navigation apparatus is required to be downsized from the aspect of securing more room in a vehicle compartment in recent years. For example, it is desired to prepare an audio-integrated apparatus, in which a navigation apparatus is united or integrated with an audio apparatus. Such an audio-integrated apparatus should include all the functions of an audio apparatus, a navigation apparatus, and a display apparatus in a usual mount space or dimensions, which has a usual DIN size. Herein, DIN signifies Deutsche Industrie Normen, namely, German industrial standard. The size of 50 mm high and 178 mm wide is called “1 DIN” while the size of 100 mm high and 178 mm wide is called “2 DIN.” Under such a circumstance, the audio-integrated apparatus is often provided with a display movement mechanism. Further, all those functions are required to be mounted in DIN size, thereby increasing a heat dissipation per cubic volume and operating sounds of the cooling fan(s) in the apparatus. This may involve a problem.
The above technologies described in Patent documents 1 to 3 do not indicate a control of the cooling fan with respect to the states of the display movement mechanism in the audio-integrated apparatus. In addition, although referring to a relation between the cooling fan control and the operation sounds, no consideration is made to a dew condensation inside the apparatus accompanying the cooling air capacity increase and dust entry.
Herein, the audio-integrated apparatus is provided with the display movement mechanism from the following reasons:
(1) easy loading and unloading of musical media by exposing a front face of an audio section;
(2) matching a sight line of a vehicle occupant by adjusting an angle or inclination of a display unit; and
(3) storing the display unit when the display function is unnecessary.